<!DOCTYPE html>
<html lang="en">
  <head>
    <title>css阻塞</title>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <style>
      h1 {
        color: red !important;
      }
    </style>
    <script src="./1.js"></script>
    <!-- <link
      href="https://cdn.bootcss.com/bootstrap/4.0.0-alpha.6/css/bootstrap.css"
      rel="stylesheet"
    /> -->
  </head>
  <body>
    <h1>这是红色的</h1>
  </body>
  <!-- 
    结论:
      js解析会阻塞dom的解析和渲染
      css加载不会阻塞DOM树的解析
      css加载会阻塞DOM树的渲染
      css加载会阻塞后面js语句的执行、

   -->
</html>
